1.14.1　线程优先级的继承特性

在Java中，线程的优先级具有继承性，比如A线程启动B线程，则B线程的优先级与A是一样的。

创建t18项目，创建MyThread1.java文件，代码如下：

---

package extthread;

public class MyThread1 extends Thread {
@Override
public void run() {
    System.out.println("MyThread1 run priority=" + this.getPriority());
    MyThread2 thread2 = new MyThread2();
    thread2.start();
}
}

---

创建MyThread2.java文件，代码如下：

---

package extthread;

public class MyThread2 extends Thread {
@Override
public void run() {
    System.out.println("MyThread2 run priority=" + this.getPriority());
}
}

---

文件Run.java代码如下：

---

package test;

import extthread.MyThread1;

public class Run {
public static void main(String[] args) {
    System.out.println("main thread begin priority="
        + Thread.currentThread().getPriority());
    // Thread.currentThread().setPriority(6);
    System.out.println("main thread end   priority="
        + Thread.currentThread().getPriority());
    MyThread1 thread1 = new MyThread1();
    thread1.start();
}
}

---

程序运行结果如图1-62所示。

将代码：

---

// Thread.currentThread().setPriority(6);

---

前的注释去掉，再次运行Run.java文件，结果如图1-63所示。

图1-62　优先级被继承

图1-63　优先级被更改再继续继承